Spinal rod curving instrument and method for using same

ABSTRACT

A surgical rod curving method and apparatus is disclosed, wherein a rod curving force is applied to the rod by a rod curving element while the rod is moved in a lengthwise direction relative to the rod curving element. In this manner a smooth curve is induced into the rod, wherein there is substantially no localized stress points induced into the rod. Additionally, by rotating a previously curved rod about an axis corresponding to a lengthwise direction of the rod, and reapplying a curving force, a non-planar curve is induced in the surgical rod.

FIELD OF THE INVENTION

[0001] The present invention is related to the curving of surgical rodssuch as rods that are implanted into a patient's back.

BACKGROUND OF THE INVENTION

[0002] Hundreds of thousands of people, both young and old, suffer froma variety of spinal curvature deformities including scoliosis, kyphosisand loss of lumbar lardosis. More severe spinal curvature conditions mayrequire surgery whereby one or more strong yet light weight surgicalrods, typically made of a titanium alloy or surgical stainless steel,are inserted into the patient's back to assist in the fusion of thespinal column for aligning the spine in a desired configuration. Suchrods are used to realign a patient's spine and maintain it in such arealigned orientation while allowing the patient to resume substantiallynormal activities. Accordingly, such surgical rods must be at least asstrong as the bones to which they are attached, and additionally must beextremely durable. However, these rods also must be able to be shaped tothe desired contour so that they properly align the patient's spine.

[0003] Thus, before implanting such a surgical rod in patient, it isdesirable to curve the surgical rod to better fit the patient's currentspinal curvature and/or desired spinal curvature. While a variety ofsurgical rod bending devices have been developed to shape a surgical rodprior to inserting it into the human body, these devices are plaguedwith a variety of shortcomings. For example, many of these devicesrequire great force to bend the surgical rod and are thus tedious andinconvenient for the user. Further, because of the material comprisingthe surgical rods must be resistant to deforming, these devicestypically fail to curve the surgical rod accurately and/or smoothly. Forexample, these devices typically exert the bending forces on relativelysmall discrete cross sectional locations along the rod to thereby make aseries of small but discrete angular bends along the surgical rod. Suchbends may be characterized as follows: as the length of the rod istraversed, immediately prior to encountering a bend, the curvature ofthe rod has some initial curvature and the curvature of the rodtypically rises, from this initial curvature, to a maximum curvature atthe apex of the bend, and then returns to a lower value for a portion ofthe rod immediately following the bend apex. Moreover, the rise in thecurvature at the bend is, say, two to three times the initial curvature,and likely two to three times the rod curvature following the bend apex.

[0004] However, regardless of the characterization of such a bend, theapplication of bending forces at relatively small cross sectionallocations discretely spaced along the rod's length induces weaknesses inthe durability of the rod at such bending locations. Moreover, therelatively abrupt curvature changes associated with such bends are alsobelieved to contribute to rod failure after being surgically implantedin a patient. Although not being bound by any particular theory as tothe failures of such rods, it is believed that, e.g., vibrations andstresses induced in the rod by normal or typical patient movements andjarring do not effect the rod uniformly. In particular, such vibrationsand/or stresses are not transmitted as easily across such a bend. Thus,there is a disproportional amount of the forces of such vibrationsand/or stresses expended at such bends rather than being transmittedthroughout or along the rod and desirably dissipated through the ends ofthe rod. Accordingly, over months or years, such vibrations and/orstresses can cause such a rod to break where such a bend has beeninduced into the rod.

[0005] In addition, such prior art rod bending devices may induceundesirable rod surface abnormalities such as fractures, notches,marring or blemishes in the surface of a surgical rod during bending.Such surface abnormalities can also compromise the durability of animplanted rod. In particular, a rod implanted with such a surfaceabnormality can, over time, break due to, e.g., vibrations and/orstresses of normal patient activities being disproportionately absorbedby rod areas having such abnormalities.

[0006] Moreover, despite the fact that the patient's spine may beabnormally curved along multiple dimensions (and accordingly can oftenrequire correction in multiple directions), the prior art devices do noteasily allow the user to bend the surgical rod along different axes.

[0007] Thus, it would be desirable to have a surgical rod shapingapparatus and method of use, wherein such a surgical rod can be curved,e.g., during a surgical implant procedure, without inducing localizedweaknesses in the rod, and without inducing abrupt curvature changes inthe rod due to bending forces being focused on one or more discretelocations along the length of the rod. In particular, it would bedesirable to provide smooth continuous curves in such rods. Moreover, itwould be desirable to curve such surgical rods without introducingsurface abnormalities in the rod. The present invention is intended toovercome at least the above described problems with prior art surgicalrod shaping (e.g., bending) apparatuses and methods.

SUMMARY OF THE INVENTION

[0008] The present invention is a surgical rod curving apparatus andmethod for providing curves in surgical rods that, e.g., are implantedinto patients to reduce a severity of a spinal abnormality. Inparticular, the present invention induces smooth, curves into surgicalrods, such that there is a reduction or elimination of material stresspoints (also denoted in the art as “stress risers”) in the rods. Moreparticularly, the present invention applies a rod curving force ortension laterally to such a rod while the rod is moved in asubstantially transverse direction that corresponds to the length of therod. Thus, a force for contouring a rod is uniformly distributed over alength of the rod rather than applied to discrete spaced apart pointsalong the rod's length. That is, the force is successively applied to acontinuous line of points along a desired lengthwise extent of the rod(denoted herein as the force being “rolled along the rod”). Thus, forexample, the force may be moved along the length of the rod by, e.g.,moving the rod lengthwise through the desired length while the force isstationary thereby continuously applying the force to points along therod. Accordingly, the present invention induces a curving force into therod, where the force is applied over a sufficient lengthwise extent ofthe rod so as to provide a smooth curve with substantially no points onthe rod where vibrations and/or stresses can induce localized weaknessesin the rod.

[0009] Moreover, it is an aspect of the invention that when inducingsuch curves that do not have localized weaknesses (e.g., bends and/orsurface abnormalities), a rod is deformed in a manner that is moresimilar to an extruding action than a bending action in that thestructural integrity of the rod is maintained. In particular, thecurving of a surgical rod with the present invention may be an iterativeprocess, wherein each of a plurality of the lateral curving forces isapplied continuously across a length of the rod (as described above) tosuccessively curve the rod more. Moreover, each such lateral curvingforce may not be sufficient, upon first contact with the rod, to inducea deflection in the rod that would not produce a bend in the rod whichwill stay once the force is removed. That is, upon first contacting therod, such a rod curving force may only be sufficient to deflect thecurvature of the rod without inducing a bend that would be retained inthe rod upon removal of the force. However, it is an important aspect ofthe present invention that as such a lateral curving force is rolledalong the rod, a deformation of the rod occurs which is retained oncethe force is removed. Accordingly, by iteratively rolling a plurality ofsuch forces over a particular portion of the rod, a desired curve can becreated in the rod.

[0010] Other features and benefits of the present invention will becomeevident from the accompanying drawings and the detailed descriptionhereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view of a fully assembled first embodimentof the surgical rod curving apparatus 10 of the present invention.

[0012]FIG. 2 shows the apparatus 10 of FIG. 1 with the top plate 68removed.

[0013]FIGS. 3A and 3B show the apparatus 10 of FIG. 1 with the top plate68 and the driving roller subassembly 44 removed (FIG. 3A), and flippedover to show their lower sides (FIG. 3B).

[0014]FIG. 4 shows a more detailed view of driving roller subassembly44.

[0015]FIG. 5 shows a more detailed view of the assembled rod contactingcomponents of the rod curving apparatus 10 with the top plate 68removed.

DETAILED DESCRIPTION OF THE INVENTION:

[0016]FIGS. 1 and 2 show an embodiment of a surgical rod curvingapparatus 10 according to the present invention, wherein the apparatus10 is supported on a substantially horizontal surface 12. In describingthe rod curving apparatus 10, all references hereinafter indicative ofan orientation such as vertical, horizontal, upper, lower are to beunderstood as referring to the rod curving apparatus 10 as oriented inFIG. 1 relative to the surface 12. Thus, a components closer to thesurface 12 may be described as being “lower”, components further fromthe surface 12 may be described as being “upper”, orientationssubstantially perpendicular to the surface 12 will also be denoted as“vertical”, and orientations parallel with the surface 12 will also bedenoted as “horizontal”. However, as one skilled in the art willrecognize after reviewing the description and the drawings herein, otherembodiments of the rod curving apparatus 10 may be provided in otherorientations such as being attached to a vertical surface.

[0017] The surgical rod curving apparatus 10 includes a base 16 of,e.g., 304 stainless steel. The base 16 is approximately eight inches byfour inches and has a center portion 20 that is raised above the surface12 by approximately three to five inches. Secured to the side (denotedthe “upper side” herein) of the center portion 20 furthest from, andfacing away from, the surface 12 is a frame 24 of, e.g., 304 stainlesssteel. The frame 24 includes a lower plate 28 fixed to the upper side ofthe center portion 20, and two side plates 32 (FIG. 2) that are attachedto the lower plate 28. The side plates 32 have a vertical width ofapproximately one inch to 1½ inches, a horizontal length ofapproximately three to four inches, and a thickness of approximately ⅛inch.

[0018] Attached to the frame 24 is a force inducing assembly 36 (FIGS.1, 2 and particularly 3) for providing a force in the direction of arrow40 (FIG. 2) for thereby urging a curve driving roller subassembly 44(also denoted herein as a driving roller subassembly) into contact witha rod 14 for administering a rod curving force laterally to the rod 14.The force inducing assembly 36 includes a threaded anchor 48 that issecured to the lower plate 28 by, e.g., welding thereto. Through acentral portion of the anchor 48 is a threaded bore 52 that is generallyaligned with the arrow 40. Within the bore 52 is a mating threaded shaft56 which at one end is attached to an adjustment knob 60 by which theshaft 56 may be rotated so that the opposite end 64 of the shaft 56 ismovable both in the direction of arrow 40, and in the oppositedirection. Note that the center portion 20 is raised sufficiently sothat the adjustment knob 60 is easily rotated by a user without thesurface 12 interfering with such rotations. In particular, the lowestportion of the adjustment knob 60 is at least ½ inch from the surface12, and preferably between ½ and ¾ of an inch. However, the adjustmentknob 60 has a sufficiently large diameter so that a user can, in manyrod curving adjustments, grip the adjustment knob and manually turn it.Thus, in the embodiment of FIG. 1, the adjustment knob 60 has a diameterof approximately 2 to 2¼ inches.

[0019]FIGS. 3A and 3B shows the rod curving apparatus 10 partiallydisassembled so that certain interior components can be shown. Inparticular, a top plate 68 (which in FIG. 1 is attached as a top coverof the apparatus 10) is shown flipped over. Additionally the drivingroller subassembly 44 is shown flipped over from its operative positionwhen the rod curving apparatus 10 is fully assembled. Thus, also shownin FIG. 3B is the side 72 of the driving roller subassembly 44 havingthe two gears 76 and 80 thereon, and that faces the recessed and/or cutout portions 84 of the lower plate 28 when the apparatus 10 is fullyassembled. Moreover FIG. 3A shows the edges 88 and 92 of the recessedportion 84, wherein these edges follow the contours of various portionsof the side 72 together with contours of the gears 76 and 80. When therod curving apparatus 10 is fully assembled, the portion of the shaft 56protruding from anchor 48 near the shaft end 64 extends through slot 96of the bifurcated shaft connector 100 and contacts the plate 104 (bestshown in FIG. 4). Moreover, a groove 102 in the shaft 56 mates with thebifurcated shaft connector 100 so that the groove fits within the slot96 and remains within the slot during operation due to the fact that thediameter of the shaft outside of the groove is larger than the slot 96.Additionally, the groove 102 is positioned on the shaft 56 so that theextent of the shaft from the groove to the shaft end 64 is of sufficientlength so that the shaft end 64 exerts substantially all of the forcesfor curving a rod 14 against the plate 104. Thus, upon rotating theadjustment knob 60 to lengthen the portion of the shaft 56 protrudingfrom the same end of the anchor 48 as the shaft end 64, the shaft end 64presses against the plate 104 thereby urging the driving rollersubassembly 44 in the direction of arrow 40 (i.e., toward the rod 14).Conversely, upon rotating the adjustment knob 60 in the oppositedirection to thereby shorten the portion of the shaft 56 protruding fromthe same end of the anchor 48 as the shaft end 64, the groove 102 andits mating shaft connector 100 move away from the rod 14 (i.e., in theopposite direction from arrow 40). Accordingly, the entire drivingroller subassembly 44 moves in the opposite direction from arrow 40,thereby reducing a curving tension on a rod 14 being curved, and/orcreating a (wider) gap between the driving roller subassembly 44 and therod 14.

[0020] As FIG. 4 shows, the driving roller subassembly 44 also includestwo substantially parallel alignment plates 108 and 112 which areattached to one another in a fixed spaced apart relationship by, e.g.,at least one connector 116 for securing the alignment plates 108 and 112together by, e.g., by welding. Additionally, the driving rollersubassembly 44 includes a driving roller 120 that is rotatable on anaxle 124 (FIGS. 2 and 5), wherein the driving roller 120 contacts a rod14 to be curved and exerts a curving force thereto as will be more fullydescribed hereinbelow. Note that such a rod curving force may be in therange of 2,000 pounds, and accordingly, to assure the durability of thedriving roller 120, it may be manufactured from 440C stainless steel, asone skilled in the art will understand. Referring to the axle 124, it isjournaled into each of the alignment plates 108 and 112. There arebearings 126 provided on the axle to allow rotation of the drivingroller 120. these bearing 126 are non-sealed non-lubricated bearingswhich are shrink fitted to the axle 124. However, sealed bearing mayalso be used if they are of a type that can be sterilized by, e.g.,autoclaving, without degrading. Note that the gear 80 is fixedlyattached to an end of the axle 124 for thereby rotating the drivingroller 120 when the gear 80 is urged to rotate by a counter rotation ofthe gear 76. The gear ratio of the gear 76 to gear 80 may be in a rangeof 2:1 to 5:1, and more preferably 3:1. Moreover, note that the gear 76is fixedly attached to an end of an axle 128 which is journaled intoeach of the alignment plates 108 and 112, and wherein the opposite endof the axle 128 has a crank 132 attached thereto, but offset from thealignment plate 112 with a spacer 134 therebetween. The crank 132, inturn, includes a grip 136 by which a user may rotate the axle 128 andthereby rotate the driving roller 120.

[0021] In FIGS. 1, 2 and particularly 5, these figures also show twocounter rollers 140 whereby a surgical rod 14 is held between thedriving roller 120 on one side of the rod, and the counter rollers onanother side of the rod. Accordingly, the counter rollers 140 providecounter forces to the rod curving force induced in a rod 14 by thedriving roller 120 when this latter roller is urged in the direction ofarrow 40 (FIG. 5) and thereby inducing the rod to deflect into the voidspace 142 between the counter rollers 140. Note that, as with thedriving roller 120, the counter rollers 140 may be manufactured from amore stress resistant material than other components of the presentinvention. In particular, the counter rollers 140 may be also composedof 440C stainless steel.

[0022] Each of the counter rollers 140, and the driving roller 120includes a respective channel about its circumference for retaining arod 14 therein. In particular, the counter rollers 140 have channels 146and the driving roller 120 has a channel 150. Currently, surgical rods14 have a circular cross section with a diameter of approximately ¼ to{fraction (3/16)} inch, and, in the present embodiment, each of thechannels 146 and 150 is configured to securely grip each rod 14 withoutmarring or blemishing it. Thus, it has been determined by the Applicantthat appropriate gripping without marring or blemishing rods 14 occurswhen each of the channels 146 and 150 have a contour that follows thecross sectional contour of such rods up to a maximum channel width ofapproximately the diameter of such rods, and such channels have a depthof approximately the radius of such rods. However, it is important tonote that the present invention is not limited to surgical rods 14having a circular cross section. In fact, for substantially any surgicalrod having a convex cross section appropriate channel 146 and 150contours can be provided. However, note that the channel 146 may bedifferently shaped from the channel 150. As a simple example, if thereis a rod 14 having an isosceles triangular cross section, then in oneembodiment, the channels 146 may be substantially flat in cross sectionfor contacting an entire width of a side of the rod 14. However, suchalternatively shaped channels 146 may also have a small lip on side ofthe flat portion of the channel for assuring that the rod remains in thechannel during a rod curving operation. Alternatively, for rods 14 withsuch triangularly shaped cross sections, the channel 150 may have asubstantially “V” cross section for thereby mating with a portion of therod about an edge on the rod corresponding with a vertex of the rod'striangular cross section. One skilled in the art will appreciate thatother rod cross sectional shapes can be readily curved by an embodimentof the present invention. For example, for a given rod 14 cross sectionsize and shape, a corresponding driving roller 120 and counter rollers140 can be provided having channels 146 and 150, respectively, withcross sectional shapes that substantially mate with the cross sectionalshape of the given rod 14 to be curved. Thus, embodiments of thesurgical rod curving apparatus 10 may be provided for rod 14 having,e.g., hexagonal, elliptical, or trapezoidal in shape.

[0023] The counter rollers 140 are sandwiched between retaining plates170, wherein each of the counter rollers is secured to the retainingplates 170 by a corresponding cylindrical vertical shaft (not shown)traversing the space between the retaining plates. In particular, eachcounter roller 140 is journaled on its corresponding shaft for rotatingwhile maintaining a rod 14 to be curved at a substantially constantoffset from the shaft about which it rotates. Note that the dimensionsof the retaining plates 170 are approximately 1¼×4×¼ inches, the shaftsabout which the counter rollers 140 rotate are approximately 3 to 4inches apart (and more preferably 3 to 3½ inches apart), and the counterrollers 140 as well as the driving roller 120 are approximately 1¼ to 1½inches in diameter and approximately ⅜ inches thick. Moreover, it isimportant to note that variations from these dimension ranges are withinthe scope of the present invention. For example, the counter rollers 140may be spaced as closely as about 2 inches if, e.g., the diameter of thecounter rollers and the driving roller 120 is appropriately reduced to,e.g., ¾ to 1 inch. However, with such smaller dimensions there is anincrease in the force required to curve a rod 14, and with the smallerdiameter driving roller 120 there is a greater chance of accidentallyinducing a pronounced bend in a surgical rod 14. Nevertheless, forsurgical rods 14 of smaller diameter than ¼ inches, and/or for inducingsmooth rod curves of greater curvature, such a reduced dimensionembodiment of the present invention may be appropriate.

[0024] As noted above, the majority of the surgical rod curvingapparatus 10 may be made from stainless steel for strength, durability,and for repeatedly withstanding sterilization. However, other materialsmay also be used such as carbon or graphite compounds, ceramics orplastics, in some cases depending upon the strength requirements desiredin a particular rod curving apparatus component. For example, thefollowing components: the base 16, the grip 136, the top plate 68, thespacer 134, and/or the adjustment knob 60 may not be subjected to asextreme forces and/or stresses as the forces generated on the rodcurving force and counter force generating and conducting components(e.g., the force inducing assembly 36, the curving force conductingcomponents of the driving roller subassembly 44 and the counter rollers140 together with their retaining plates 170). Thus, one or more of thecomponents that do not experience the rod 14 curving forces/stresses maybe made of, e.g., an appropriate durable plastic, a graphite compositeand/or other material that both does not degrade during a sterilizationprocess (e.g., autoclaving), and is acceptable for use in the context ofa surgical procedure (e.g., is non-toxic and does not compromise thesterile conditions of an operating room). In particular, although theembodiment of the rod curving apparatus 10 in FIGS. 1-5 is notexcessively heavy (e.g., about 5.5 pounds), a lighter embodiment may beprovided by manufacturing at least some components, such as thoseidentified above, out of one or more materials rather than stainlesssteel. Moreover, by providing a lighter embodiment of the presentinvention, additional conveniences may be more easily provided withoutthe surgical rod curving apparatus 10 becoming unwieldy. For example,table clamps and/or fittings may be integrated into the embodiment shownin FIGS. 1-5 so that the apparatus 10 is less prone to move during a rod14 curving process.

[0025] Referring again to FIG. 1, this figure also shows an adjustmentarm 180 that is insertable into any one of a plurality bores 184provided about the circumference of the adjustment knob 60, and inparticular, at least eight equally spaced such bores about theadjustment knob circumference. The adjustment arm 180 allows a user tomore easily rotate the shaft 56 in the direction for thereby moving thedriving roller 120 laterally into a rod 14.

[0026] Additionally, FIG. 1 shows a handle 190 for attaching to the endof rods 14 so that during a curving of such a rod by the presentinvention, the rod can be maintained in a desired orientation. Inparticular, upon applying repeated curving operations to a rod 14, therod may tend to twist somewhat about its longitudinal axis and thus theresulting curve may be in an undesirable plane or the resulting curvemay be non-planar when a planar curve is desired. The handle 190includes a hand grip 194 by which a user can orient a rod being curved,and a rod holding portion 198 for fixedly securing a rod 14 and thehandle together. The rod holding portion 198 includes a rod insertionbore 204 for inserting rods 14 therein, and a wing nut 208 that threadsinto a mating threaded opening 212 that: (a) is perpendicular to the rodinsertion bore 204, and (b) opens into the rod insertion bore so thatthe threaded end of the wing nut can contact a rod 14 therein and securethe handle and the rod together. Additionally, the enclosed end of therod insertion bore 204, that is toward the hand grip 194, may have ahexagonal configuration for mating with ends of rods 14 that arehexagonal in shape. In particular, many surgical rods 14 made oftitanium have such a hexagonal shaped end. Accordingly, by attaching thehandle 190 securely to the end a rod 14 so that the handle and the rodrotate and move in unison, a user can prohibit such non-desirable rodtwists when curving the rod, or alternatively, the user may inducecompound 3-dimensional curves into the rod by purposely changing theorientation of the handle 190 between successive applications of curveinducing forces by the present invention.

[0027] In operation a user may first determine the desired curve toinduce in a rod 14. The user may wish to identify one or more portionsof the rod 14 to be curved by, e.g., providing removable markings on therod identifying the longitudinal extent(s) of the rod that is to becurved. Subsequently, the user may insert an end of the rod 14 into therod insertion bore 204 of the handle 190, and secure the rod and thehandle together by, e.g., tightening the wing nut 208 in the opening 208so that the threaded end of the wing nut is secured against the rod.Then the opposite end of the rod 14 is threaded into the rod curvingapparatus 10 so that the rod is seated within each of the channels 146of the counter rollers 140, and additionally, is also seated in thechannel 150 of the driving roller 120. Note that to seat the rod 14, theuser may have to adjust the position of the driving roller 120 byrotating the adjustment knob 60 so that the rod can threaded into thechannels 146 on one side, and the channel 150 on the other. The userthen positions the rod 14 within the apparatus 10 so that for (a marked)longitudinal extent of the rod wherein this extent is to be curved, thechannel 150 of the driving roller 120 contacts the rod approximately inthe middle of this extent. The user may, if not already performed, noteand/or change the orientation of the hand grip 194 so that any twistingof the rod 14 during the curving operation may be prohibited and/or isperformed as the user desires (e.g., by manually and purposefullytwisting the rod as the rod is being curved). In one method ofoperation, the user may orient the hand grip 194 so that it is parallelto the surface 12 initially, and since it is believed that most rodcurves will be planar, in such cases, the user need only hold the handgrip during the rod curving process so as to maintain the grip'sparallel orientation to the surface 12. Thus, once the hand grip 194 isoriented as desired, the user may then rotate the adjustment knob 60 soas to move the driving roller 120 to laterally deflect the rod 14between the counter rollers 140. It is important to note that preferablythe user should turn the adjustment knob 60 (directly or by use of theadjustment arm 180) only enough to cause the rod to deflect wherein theinherent resiliency of the rod would return the rod to its initialstraight configuration if the laterally deflecting force exerted bydriving roller 120 were removed. Accordingly, for the embodiment of therod curving apparatus 10 shown in FIGS. 1-5, wherein the counter rollers140 are approximately 3 to 3½ inches apart, the rod 14 is ¼ inch indiameter, and the rod is stainless steel or titanium, under theseconditions no more than {fraction (1/16)} of an inch of deflection ispreferred, and more preferably between {fraction (1/16)} and {fraction(1/32)} of an inch deflection. Thus, in the embodiment of FIGS. 1-5, roddeflection of {fraction (1/16)} to {fraction (1/32)} of an inchesamounts to approximately ¼ to ⅛ of a turn of the adjustment knob 60.

[0028] Accordingly, once the rod 14 is initially deflected by thelateral contact of the driving roller 120, the user then grasps the grip136 on the crank 132 and revolves the crank and thereby rotate thedriving roller 120. Note that there is sufficient tension, due to theresiliency of the rod 14, between the driving roller and rod so that therod will move substantially synchronously with the rotation of thedriving roller 120. That is, the rod 14 moves in a directioncorresponding to its longitudinal axis (i.e., in one of the directionsidentified by the arrow 216 in FIG. 1) without the driving roller 120slipping or skidding along the surface of the rod. Generally, the userwill cause the rod 14 to move in both of the longitudinal axisdirections most of the entire length of the extent of the rod to becurved. In particular, the user may cause the driving roller 120 to rollback and forth along the portion of the longitudinal extent, E. of therod 14 to be curved, wherein the driving roller does not generally rollbeyond a point where either of the extremes of the rod extent E comebetween the rod contact points of the two counter rollers 140. Thus, inthe embodiment of FIGS. 1-5 this means that the driving roller 120 rollsalong the portion of the rod within E that is approximately 1½ to 1¾inches shorter on both ends of E. Further note that since the drivingroller 120 is midway between the two counter rollers 140, substantiallythe same curve is induced in the rod 14 regardless of the longitudinalaxis direction that the driving roller is rolled.

[0029] It is important to note that although the deflecting forceinduced by the drive roller 120 does not bend the rod 14 beyond itsresiliency or elasticity limits at any one point along the rod 14, therod none-the-less retains a deformation when this force rolled along anextent of the rod. Moreover, instead of weakening the rod 14, it isbelieved that in fact the rod may become sturdier due to the curvingprocess.

[0030] Once the driving roller 120 is rolled at once over theappropriate portion of the longitudinal extent E, the user then turnsthe adjustment knob 60 again to deflect the rod 14 an additional amount(e.g., up to another {fraction (1/16)} of an inch) and again revolvesthe crank 132 to thereby roll the driving roller 120 over substantiallythe same portion of the rod as in the first iteration of rolling above.Thus, curving the rod 14 an additional amount. By repeatedly alternatingbetween causing the driving roller 120 to move further in the directionof arrow 40 and rolling the driving roller over a portion of the rod,the rod is progressively deformed into a desired curve. Moreover, forincreasing the curvature of, e.g., a central portion of a particularcurve, the longitudinal portion of the rod 14 that is rolled may, insome cases, become progressively less with further iterations.

[0031] Note that with each iteration of rolling the driving roller 120over the rod 14, the user is able to readily view the curving processdue substantially to the cut out 220 (FIG. 1). Thus, the user candetermine while the rod 14 is engaged in the apparatus 10 whether thedesired curve is being provided to the rod. Moreover, if such a curvebecomes unacceptable, the user can easily remove the objectionableportion of the curve by removing any driving roller 120 tension beingplaced on the rod, rotating the rod so that the hand grip 194 is turned180 degrees (i.e., the rod can be reversed in angular orientation aboutan axis parallel to a vector tangential to the length of the rod at thehandle 190), and then commencing to repeatedly alternate between causingthe driving roller 120 to move further in the direction of arrow 40 androlling the driving roller over a portion of the rod until theundesirable deformation of the curve is removed.

[0032] Accordingly, once a desired curve is induced into such a surgicalrod 14, the rod may be then implanted into a patient. Note that it isbelieved that the method and apparatus of the curving surgical rods ofthe present invention is particularly suited for use in operating roomsduring corrective spinal surgery. At least some of the characteristicsthat are desirable in this context are that the apparatus 10 may besmall (e.g., 4 inches by 8 inches), relatively light weight, easilyportable or carried manually by one person, e.g., to various locationswithin an operating room, does not require substantial technicaltraining that is peculiar to the apparatus. Moreover, it is anadditional important feature of the apparatus 10 that the componentsthat fit together (such as the threaded shaft 56 and the anchor 48, and,the rollers and their adjacent components) are sufficiently looselyfitting so that the apparatus can be sterilized in, e.g., an autoclavewithout disassembling.

[0033] The foregoing discussion of the invention has been presented forpurposes of illustration and description. Further, the description isnot intended to limit the invention to the form disclosed herein.Consequently, variations and modifications commensurate with the aboveteachings, within the skill and knowledge of the relevant art, arewithin the scope of the present invention. The embodiments describedhereinabove are further intended to explain the best mode presentlyknown of practicing the invention and to enable others skilled in theart to utilize the invention in such or in other embodiments and withvarious modifications required by their particular application or use ofthe invention. It is intended that the appended claims be construed toinclude the alternative embodiments to the extent permitted by the priorart.

What is claimed is:
 1. A surgical rod curving apparatus comprising: afirst component for applying a first force to a surgical rod, whereinsaid first component includes a first element wherein said first elementapplies the first force traversely to a lengthwise direction of the rod,and applies the first force substantially continuously along a length ofthe rod, when said first element traverses the length of the rod; secondand third elements for applying respective counter forces during theapplication of the first force, wherein when said first elementtraverses the length of the rod, each of said second and third elementstraverse a corresponding length of the rod and apply their respectivecounter force substantially continuously their corresponding length ofthe rod; wherein said first force and said counter forces induce a curvein the rod when said first element traverses the length; wherein whenthe rod is curved, the rod is implanted in a patient.
 2. The surgicalrod curving apparatus of claim 1, wherein each of said first, second andthird elements revolve when the rod is moved relative to said firstelement.
 3. The surgical rod curving apparatus of claim 2, wherein eachof said first, second and third elements contact the rod when revolving.4. The surgical rod curving apparatus of claim 1, wherein at least oneof said first, second and third elements includes a roller with achannel for mating with a contour of the rod.
 5. The surgical rodcurving apparatus of claim 1, wherein said first element contacts therod between rod contacts by said second and third elements.
 6. Thesurgical rod curving apparatus of claim 5, wherein said first elementcontacts the rod substantially midway between where said second andthird elements contact the rod.
 7. The surgical rod curving apparatus ofclaim 1, wherein said apparatus can be transported manually by oneperson.
 8. The surgical rod curving apparatus of claim 1, wherein saidfirst force is applied substantially laterally relative to the length ofthe rod.
 9. The surgical rod curving apparatus of claim 1, wherein thecurved surgical rod is for reducing a severity of a spinal abnormality.10. The surgical rod curving apparatus of claim 1, wherein said firstcomponent includes a shaft having an adjuster at one end of the shaftfor moving an opposite end of the shaft relative to the rod.
 11. Thesurgical rod curving apparatus of claim 10, wherein said shaft is fortransmitting the first force to said first element, and wherein saidshaft includes a groove for mating with a slot of a shaft connector formoving said first element substantially synchronously said shaft bothtoward and away from the rod.
 12. The surgical rod curving apparatus ofclaim 10, wherein said adjuster includes a rotatable knob for rotatingthe shaft.
 13. The surgical rod curving apparatus of claim 10, whereinsaid adjuster includes an adjustment arm that extends outwardly from theshaft thereby providing a user with additional leverage for rotating theshaft, wherein said arm can be provided in a plurality of operableorientations relative to an orientation of the shaft.
 14. The surgicalrod curving apparatus of claim 10, wherein said opposite end of theshaft movably contacts a subassembly having a first axle about which atleast a portion of said first element rotates.
 15. The surgical rodcurving apparatus of claim 14, wherein said subassembly includes atleast two gears for performing a gear reduction between a rotation of asecond axle and a rotation of the first axle.
 16. The surgical rodcurving apparatus of claim 1, wherein said second and third elements arespaced apart by a distance of 3 to 4 inches.
 17. The surgical rodcurving apparatus of claim 1, wherein said first component includes acrank for urging said first element to traverse the length of the rod.18. The surgical rod curving apparatus as in claim 1, further comprisingat least one roller included in each of the first, second and thirdelements, each said roller contacting the surgical rod.
 19. A surgicalrod curving apparatus, comprising: a force providing assembly forapplying a first force to a rigid surgical rod, wherein said first forceis applied substantially laterally to a lengthwise direction of thesurgical rod; second and third rod contacting portions for applyingrespective counter forces to the first force; a rod moving mechanism formoving the surgical rod relative to one or more of said force providingassembly, said second rod contacting portion and said third rodcontacting portion, wherein the first force is applied substantiallycontinuously to the surgical rod during the moving of the surgical rod;wherein said first force and said counter forces induce a curve in therod during the moving of the rod; wherein when subsequent to the rodbeing curved, it is implanted in a patient.
 20. The surgical rod curvingapparatus of claim 19, further including a base that supports said forceproviding assembly, and said first and second contacting portions,wherein said base supports said apparatus on a surface in a surgicaloperating room.
 21. The surgical rod curving apparatus of claim 19,wherein said force providing assembly and said rod moving mechanisminclude a common component, said common component including a roller forapplying said first force to the rod, and for providing the moving ofthe rod.
 22. A method of curving a rigid surgical rod, comprising:positioning the rigid surgical rod between opposing first and second rodcontacting portion; moving the rod along its longitudinal extent whilesubstantially continuously exerting a substantially lateral force on therod by at least one of said first and second rod contacting portions;applying an angular force to a handle connected to the rod for obtainingone or more desired angular orientations of the surgical rod about itslongitudinal extent while said moving step is performed.
 23. The methodof claim 22, wherein said first rod contacting portion includes at leastone roller, and said second rod contacting portion includes at least tworollers.
 24. The method of claim 23, wherein said two rollers of saidsecond portion are spaced apart, and said at least one roller of thefirst portion contacts the rod between rod contacts by said two rollers.25. The method of claim 22, wherein said contacting elements have achannel that mates with a contour of the rod so that a surface of therod is not blemished.
 26. The method of claim 22, wherein saidpositioning step includes attaching said handle to the surgical rod,wherein said handle provides a visual indicator of an angularorientation of the surgical rod about its longitudinal extent;
 27. Themethod of claim 22, further including repeatedly interleaving aperforming of said steps of moving and exerting, wherein for each of therepeated steps of exerting, another substantially lateral force isapplied to the rod.
 28. The method of claim 27, wherein at least most ofthe substantially lateral forces are not sufficient to introduce apermanent deformation of the rod prior to a next performance of saidstep of moving.
 29. The method of claim 27, wherein at least oneperformance of said step of exerting includes turning an adjuster forincreasing a corresponding one of the substantially lateral forces. 30.The method of claim 22, wherein said step of moving includes revolving acrank for moving the first rod contacting portion along the longitudinalextent of the rod.
 31. The method of claim 30, wherein said moving stepincludes reducing a gear ratio between said crank and said first rodcontacting portion.
 32. A method of curving a rigid surgical rod,comprising: positioning the rigid surgical rod, along its length,between rod contacting first and second portions, wherein the rod ismovable relative to the first and second portions; exerting a rodcurving force on the rod via said first portion; moving the rod,relative to at least one of said first and second portions, in alengthwise direction while concurrently applying said curving force. 33.The method of claim 32, further including a step of exerting a counterforce to the rod curving force via said second portion, wherein saidcounter force is offset along the rod length from a point of applicationof said curving force.
 34. The method of claim 32, further includingrepeatedly interleaving a performing of said steps of exerting andmoving until a desired curve in the rod is attained, wherein for each ofthe repeated steps of exerting, another rod curving force is applied tothe rod.
 35. The method of claim 32 further including removing a curvefrom the rod, said removing step comprising: changing an angularorientation about a longitudinal direction of the rod; and reapplyingsaid steps of exerting and moving, wherein said curving force isdirected against a convex portion of the curve.
 36. The method of claim32, further including a step of implanting the rod in a patient once adesired curve is induced, wherein said steps of exerting and movingoccur during a surgery for implanting the rod.
 37. The method of claim32, further including steps of rotating the rod about an axissubstantially corresponding to a lengthwise direction, and reapplying atleast said exerting step for inducing a non-planar curve in the rod. 38.The method of claim 32, wherein said step of moving includes moving therod in two substantially opposite directions relative to said firstportion.
 39. The method of claim 32, wherein said step of movingincludes rotating at least one component of at least one of said firstand second portions.
 40. The method of claim 39, wherein said at leastone component contacts the rod, and rotates with a movement of the rod.